1. [techspeak] During the execution of a procedural language, one is
said to unwind the stack from a
called procedure up to a caller when one discards the stack frame and any
number of frames above it, popping back up to the level of the given
caller. In C this is done with longjmp/setjmp, in
LISP or C++ with throw/catch. See also
smash the stack.

2. People can unwind the stack as well, by quickly dealing with a
bunch of problems: “Oh heck, let's do lunch. Just a second while I
unwind my stack.”